Hydraulic jack



Feb. 2 1926. 1,571,602

J. ROBERTS HYDRAULIC JACK o igi al Filed March 20 1924 Patented Feb. 2,1926.

UNITED STATES PATENT OFFICE.

JAMES ROBERTS, OF TORONTO, ONTARIO, CANADA.-

HYDRAULIG JACK.

Applicationflled March 20, 1924, Serial No. 700,488. Renewed December11, 1925.

To all whom it may concern:

Be it known that I, JAMES Roennrs, a subject of the King of GreatBritain, and residing in the city of Toronto, county of York, Provinceof Ontario, Canada, ave invented certain new and useful Improvements inHydraulic Jacks, of which the following is a specification.

The principal objects of this invention 10 are, to devise a portablehydraulic jack of 7 very compact form which will lift andsustainextremely heavy loads and may be placed in very closely restrictedpositions.

The principal feature of the present in- 15 ventionconsists in the novelconstruction of the pump-operating means which enables -me to increasethe power developed by the jack without in anymanner changing theproportions of the other parts, and consequently without impairment ofthe compact form of the jack, and in the following specification I shalldescribe my invention, and what I claim as new will be set forth in theclaims forming part of this specification.

Fig. 1 is a vertical mid-central view through my jack, showing in sideelevation the operating means for the pump. Fig. 2

is a plan view, and Fig. 3 is a cross sectional I view on the line 33,Fig. 2.

In the, drawings, like characters of reference, refer to the same parts.

The base of the jack 001111111888 8, ram

chamber 1 which is of cylindncal form and a fluidreceptacle 2 whichextends to one side of the ram chamber, the top of said receptacle beingarranged about midway of t e height of the base.

The ram 3, which is here shown formed with a circular flange 4 at thetop, slides within the cylindrical orifice 5 at the top of the ramchamber and suitable packing rin s 6 are arranged in the wall of saidori ce. The top of the fluid receptacle 2 is formed with an inwardlyextending flange 7 and upon this flange is supported a pump block 8.

The block 8 fits within the rectangular orifice 9 encircled by theflange 7 and is provided with a lateral flangf 10 extending over theflange 7. A suita le packing 11 is placed between these flanges and theblock .is fastened securely by the cap screws 12. The block 8 is formedwith a projecting lug '13 having a reduced end 14 which fits into a hole15 arranged in the side of the ram block 8 is arranged a boss 16 havinga vertical orifice 17 bored therein and communic'atingat the bottom witha passage 18 which extends longitudinally of the block and to each sideofsaid orifice. I

A hole 19 extends downwardly from the outward end of the passage 18and-a length of pipe 20 extends from thebottom ofthe block close to thebottom of the receptacle 2. Avalve seat is formed at the upper end ofthe hole 19 and a ball valve 21 rests in said seat.

A screw lug 22 is arranged above the ball valve to al ow access theretoand to enable the placing of the valve.

The opposite end of the passage 18 extends upwardly in the block andcommunicates with ahorizontal passage 23 leading through the lug 13 tothe hole 15 and ram chamber 1 and at the top of the vertical portion 24of the passage 18 is arran ed a ball valve 25 .and a screw plug 26 1sarranged above said valve. plunger 27 is arranged in the orifice 17.

-A packing nut 28 is secured at the upper end of the boss 16 around theplunger. The upper endof this plunger is in the form of a slotted head29, and alever 30 extends through said slotted head. The inner end 30'of this lever is preferably bifurcated as shown in Fig. 2, and straddlesthe outer end of a connection 40, to which it is pivoted by means of thepin 41. This connection is fixedly associated with the base of the jack,after the following preferred manner: the inner end of this connectionis substantially vertically disposed as shown A cylindrical" at 42 andfits up against a portion of said P base. i A pin-43 in-substantiallythe same plane as the pin 41 and substantially parallel 'theretopasses'through portion of said base and through. the inner end of saidconnection, thus firmlysupporting said connection.

The lever 30 is provided with aligned upper and lower bosses 44 whichrest in contact with the downward curved up er and upward curved lowerends .of t e slot formed in the head 29. This construction permits ofthe maximum range of movement of the lever 30, and the. placing of thefulcrum 41 for said lever as close as practicable to the plunger 27permits me to develop greater power with the: jack than I can'developwhere the fulcrum of the lever is further away I from. said plunger.

The wider range of movement for the le ver 30 is had through the use ofthe bosses "of the same size one will be above the other,

. axis of the vide for and they will rest in contact with the apex ofeach curved. end of the slot in the head 29, and in alignmentwith thelongitudinal plunger 27. Inorder to prothe upward and downward movementof the tances, the pin 41 is located substantially in alignment with thelongitudinal axis of the leyer 30. Obviously there will be a combinedsliding-and-rolling contact, during op-- eration, between the saidbosses and the curved ends of the said slot, thus allowing for freedomof movement for said lever" without any netessity of having a looseconnection between said lever and the base" of the jack.

I have found that. the construction herein-stated and illustrated in mydrawings,

relieves the plunger 27 .ofthe action of anv 1 .torque which naturallywould bring lateral pressure against said plunger.

In the use of this jack the structure-is such as to enable it beinginserted into very restricted spaces and when the ram is insertedbeneaththe load the lever 3Q is operated to operate the pump plunger. Inthe upward stroke the plunger draws a quantity'of the fluid past thevalve 21 into the passage'lS and on the downward stroke the valve 21closes and the fluid is forced past the valve 25 into thelram chamber.The size of the plunger and the leverage are so proportioned as toenable the operation of the pump pro-- ducing very high pressures withinthe ram chamber and the eflect of pressure intro-' duced intosuidchambefl forces the ram upward to lift the load. The ball valve25being subject to the pressure within the ram chamber1efi'ective1y holdsthe fluid so that the ram may be maintained positively in any desiredposition for any'definite period.

In order to accomplish the lowering of the load a by-pass is arranged inthe block 8 and consists of a transverse opening 32 leading from thepassage 24 above the valve25 and a threaded outer end opening from thesi e of the block.

erted.

plunger 27 of equal 'dis- A hole. 33 leads downwardly from thetransversepassage through the block and communicates with the interior of thereceptacle 2. A valve 34 having a threaded stem threaded into thethreaded open end of the transverse opening 32 is adapted to engage thevalve seat to close the opening.'

This valve is closed during the operation of raising the ram and when itis desired to lower it the valve is opened to allow the outer end of thefluid receptacle to engage the pump block to force'the end of the lug'13 securely into place to maintain the joint tight under the heavypressure whlch is ex- -What I claim is:

1. An hydraulic 'ackcomprisinga base having a ram chamh'er and aseparate fluid receptacle; chamber; a ceptac'le and connected with theram chamher, and embracing a plunger having a slotted head, the upperend of said slot being curved downwardly, and the lower end thereofbeing curved upwardly, and the apexes of said curved surfaces beingsubstantially in alignment with the longitu dinal axis of. said plunger,a lever extending through said slotted head and provided at its upperand lower sides with aligned bosses projecting therebeyondwhich operatein contact with the curved upper and lower ends of said slot, and meansfixedly carried by said base and. projectin laterally 'therebeyond andto the outer en of which the inner end of said lever is pivoted so thatthe-fulcrum for said lever will be substantially in alignment with thelongitudinal axis thereof, said pump through the movement given to'saidplunger through the medium of said lever drawing fluid from said fluidreceptacle and forcing it into said ram chamber. I

2. An hydrauli'c jack comprising a base having a ram chamber and aseliarate fluid receptacle; a pum block remova ly secured in the top ofsaid fluid receptacle and having a passage .therethroughin communicationwith the'ram chamber; a pump operatively arranged in said block and incommunicate tionwith said fluid receptacle and embracing a plungerhaving a slotted head, the upper end of said slot bein curveddownwardly, and the lower end thereof bein curved upwardly, and theapexes .of said curved surfaces being substantially in alignment withthelongitudinal axis of said plunger, a lever extending ough said slottedhead and provided at its upper and lower sides with aligned bosses a ramoperating in said ram pump secured to said fillld reprojectingtherebeyond which operate in contact with the curved upper and lowerends of said slot, and means fixedly carried by said base and projectinglaterally therebeyond and to 5 the outer end of which the inner end ofsaid lever is pivoted so that the fulcrum for said lever will besubstantially in alignment with the longitudinal axis thereof, said pumpthrough the movement given to said plunger through the medium of saidlever drawing fluid from said fluid receptacles and forcing it into saidram chamber.

JAMES ROBERTS.

